Christopher Kist

The Feasibility of High-Intensity Interval Exercise in Obese Adolescents

Exercise is a critical component in the management of pediatric obesity. Currently, continuous aerobic exercise (AE) is the standard of care for pediatric weight management programs. The 2008 Physical Activity Guidelines for Americans primarily promote aerobic activity for children, and aerobic-based exercise at a steady intensity (AE) is typically prescribed in pediatric weight management programs1. Several studies in adults, however, show advantages of high-intensity interval exercise (HIIE) over continuous A Eat improving fitness and health in both healthy and obese people2–4. These benefits of HIIE compared to AE have also been demonstrated in some limited studies in children. In a sample of healthy prepubescent children, Borel et al showed the immediate effects on oxygen uptake (VO2) of HIIE to be comparable to continuous AE by continuously monitoring gas exchange of subjects at various points in an exercise protocol Farpour et al showed improved health and fitness measures in healthy children as a result of HIIE5,6. Some of this work in children extends into the obese population. Ingul et al showed that impaired cardiac function in obese adolescents can be improved by 3 months of HIIE training on a treadmill twice a week for 13 weeks7. Tjonna et al studied obese adolescents in twice weekly HIIE intervention for 12 weeks compared to subjects receiving bimonthly education from multidisciplinary health professionals8. HIIE was superior to educational classes at improving subject BMI, body fat, blood pressure, blood glucose, and endothelial function. A study from the Sao Paulo School of Medicine compared HIIE and AE in obese 8–12 year old children with treadmill training protocols twice a week for 12 weeks. Both were found to be equally effective in improving aerobic fitness, insulin sensitivity, and BMI in obese children but the study may have had too few enrolled to show a difference between modes of exercise9. While these few studies of HIIE in obese children have shown benefits on fitness and cardiovascular risk factors, the acceptability and enjoyment of this protocol in children is not clear. Enjoyment of the exercise is a crucial component if our goal is long-term adherence. Another limitation of many HIIE studies in children is restriction of the interval training to treadmill protocols; a more varied exercise protocol would be more comparable to the current standard of care, which includes group games and more variable equipment choices. The purpose of this HIIE study was to measure the enjoyment and acceptability of HIIE as well as the feasibility of a multimodal protocol in obese teenagers enrolled in a multi-disciplinary pediatric weight management program as a precursor for a larger, definitive study.

Reducing lifestyle risk in Childhood Cancer Survivors

As survival of children with serious illnesses such as cancer and heart disease has improved, lifestyle issues such as fitness, healthful eating and obesity have become long-term concerns for them (1,2). Childhood cancer survivors (CCS) now face the same lifestyle issues as the general population as the habits they establish in their youth carry over into adulthood. With their study in this journal, Dubnov-Raz et al. investigated the effects of an exercise programme on body composition, fitness and mental health in children treated for cancer. In brief, the study consisted of 22 children aged 7–14 years who had previously received chemotherapy or bone marrow transplantation (3). This study was carried out to examine the effects of physical activity on fitness, body composition and mental health of children after cancer or bone marrow transplantation. As part of this study, 10 children took part in a 6-month exercise programme, and the 12 who did not participate in the group classes formed the control group. Measures of aerobic fitness, bone density, body composition, mood and quality of life were taken before and after the intervention. An initial cardiopulmonary exercise test via cycle ergometer as well as body composition measured by a DEXA scan was performed before and after the exercise intervention. A Pediatric Quality of Life Inventory was also done to measure health-related quality of life, and mood was assessed by the CDI Children’s Depression Inventory. The exercise intervention was performed as part of a commercial programme for children and adolescents who operate year-round at a local Go-Active gym chain. This programme included three group exercise sessions per week and the participants were instructed to go continuously for 6 months. The classes included a 15-minute warm-up and a 10–15 minute cool down along with strength exercises using bands, balls, games and various cardiovascular equipment in the gym. After the 6-month intervention of 3 exercise days each week, one would expect to see a more favourable change in aerobic fitness level. However, we do not know how many group classes those in the intervention group actually went to since adherence to the classes was only verified by phone calls every 2 weeks. Also, while we know what exercises the classes consisted of, we do not really know how well the children engaged or at what level of intensity. A class that was more physically demanding and focused on cardiovascular exercise might have yielded better results and shown a greater improvement in aerobic capacity. A major strength of the study was using a maximal exercise test (cycle ergometer) to measure aerobic capacity. The author notes that most previous studies used field estimate changes in VO2. Also, finding study participants with certain types of cancers who were willing to participate would also be very difficult and explains the small sample size. The study showed no changes in aerobic fitness, body composition or mental health indices. However, the group classes focused primarily on strength and endurance exercises, so that might be one reason why the changes in aerobic capacity were not as significant as one might predict. Another explanation could have been that the intervention group was ‘healthier’ than most previous studies carried out in this population. It is expected that a group starting out with a lower fitness level would see a greater improvement with the exercise intervention. The study did show positive correlations between aerobic fitness and changes in lean body mass and bone health in all participants. Perhaps most important, the study showed that CCS can participate in a traditional exercise programme. Why CCS and those who have undergone bone marrow transplant are at risk for inactivity and poor nutrition is understandable and predictable. Health priorities change during the course of the illness, along with parenting style, goals and lifestyle (4). The children often have had prolonged hospitalisations and inactivity and confinement to bed or their rooms. Additionally, nutrition during cancer treatment focuses on maximising caloric intake. Family members are affected and schedules are disrupted, and the

A Comparison of Four Submaximal Tests for Evaluating Change in Fitness in Youth With Obesity

Obesity has more than doubled in children and quadrupled in adolescents over the past 30 years. Children with obesity are more likely to become adults with obesity and in conjunction are likely to develop disease and shortened life. In particular, type 2 diabetes mellitus was previously considered an adult disease, but is now increasing among children. Treatment of obesity involves a combination of improved diet and physical activity. However, it has been shown that body weight and activity level are more highly correlated than body weight and food intake. Physical activity also reduces the risk of cardiovascular disease and type 2 diabetes by improving plasma triglyceride levels, total cholesterol, high-density lipoprotein (HDL) cholesterol, and insulin sensitivity. In fact, it has been shown that fitness levels are a more accurate predictor of cardiovascular disease and all-cause mortality than weight status. Typically, youths with obesity have a lower cardiovascular fitness and overall physical ability to tolerate exercise than do lean youth. Low cardiovascular fitness is an important health problem in today’s youth, especially in the obese population. Excess body fat is thought to contribute to exercise intolerance and thus a lower cardiorespiratory fitness. Historically, measuring VO 2 max has been the “gold standard” for assessing the cardiovascular fitness of an individual. VO 2 is the amount of oxygen that a given individual can consume while performing dynamic exercise. VO 2 max, then, is the point at which the VO 2 plateaus and no further increase in consumption is seen with increasing workload. Maximal effort is challenging to obtain in pediatric patients, especially in children and adolescents who are obese due to the higher perceived exhaustion and erratic breathing. Because of this, submaximal measures may be of value to evaluate fitness in children with obesity. Submaximal measures such as heart rate (HR), blood pressure (BP), respiratory rate (RR), rating of perceived exertion (RPE), and breathlessness at a given exercise level have been used for evaluating fitness. Typically, the obese population has a higher submaximal heart rate when compared with that of the leaner population. With increased exercise and improvement in fitness, a decrease in submaximal measures such as VO 2 , HR, BP, and RR are seen. Change in HR (lower HR compared with HR at baseline before a fitness program), for example, has been shown to be a successful measure of cardiovascular fitness in youth and minimizes discomfort in study participants. VO 2 max has also been accurately predicted by measuring VO 2 consumption at submaximum effort. While submaximal testing has potential advantages in fitness testing in children and adolescent with obesity, the best mode of testing is still not clear. In this study, we describe a comparison between 4 submaximal tests in obese youth. Change in HR and VO 2 consumption at 6and 9-minute intervals are compared with change in VO 2 max in youth enrolled in a pediatric weight management program (PWMP).

An After-Hours Rapid Access Pediatric Weight Management Clinic Increases Show Rate:

Despite more than a decade of major public health and medical efforts, childhood obesity remains a persistently frustrating health care problem in the United States with more than 30% of children either overweight or obese. Efforts have been made to help pediatric primary care providers in obesity prevention and treatment, and pediatric weight management (PWM) programs are recommended for obese patients who do not respond to treatment in the primary care setting. Although PWM programs have favorable results, obese children and their families unfortunately often face long waits for appointments to these programs. As a result, show rates may be poor. Open access clinics that feature short waits from referral to being seen in the clinics have been successful in reducing time for appointments and improving show rates in both primary care and specialty offices. With this in mind, we developed an After-Hours Rapid Access Clinic (AHRAC) for PWM to improve access and patient show rate. In this article, we report a favorable comparison of our AHRAC with our traditional daytime clinic with respect to show rate when patients are scheduled for their initial assessment close in time to their referral.

Obese Children in a Community YMCA “Fun 2B Fit” Program Have a Reduction in BMI Z-Scores

Childhood obesity continues to be a major health problem in the United States, with more than 30% of children overweight or obese. Pediatric weight management programs have been shown to be effective, but the access to these programs are limited by capacity and regional availability. Given the magnitude of the problem, efforts have been made to educate primary care pediatric providers on the medical management of this disorder. Ancillary services, however, such as dietitian services and exercise programs geared for overweight and obese children, are often lacking in many communities. Some community-based childhood obesity efforts have addressed the physical activity component by establishing YMCA-based exercise programs. The Center for Better Health and Nutrition (CBHN) is a pediatric weight management program that includes medical evaluation and treatment for overweight and obese youth. In addition, it includes a comprehensive intervention program called HealthWorks!, which offers dietitian and exercise services. The HealthWorks! (HW) program was established in 1999 and was offered only at our main campus until 2006 when the program was expanded to include 4 community-based satellite clinics. This created the need for accompanying exercise programs at the satellite locations. We addressed this need by establishing 4 community YMCA-based exercise programs called “Fun 2B Fit” for obese and overweight children in those communities. With this study, we describe the program’s effectiveness and compare the outcome of HW children attending Fun 2B Fit with those enrolled in Fun 2B Fit alone (non-HW).